Measurements of the Congestion Responsiveness of Windows Streaming Media

Measurements of the Congestion Responsiveness of Windows Streaming Media

James Nichols, Mark Claypool, Robert Kinicki and Mingzhe Li

In Proceedings of the 14th ACM International Workshop on Network and Operating Systems Support for Digital Audio and Video
Kinsale, County Cork, Ireland
June 16-18, 2004

While previous research has shown that streaming media can respond to network congestion, it is not known to what extent commercial products are responsive. Knowledge of streaming media's response to congestion encountered in the network is important in building networks that better accommodate their turbulence. This research seeks to characterize the bitrate response of Windows Streaming Media (WSM) in response to network-level metrics such as capacity, loss rate, and round-trip time. We construct a streaming media test bed that allows us to systematically vary network and content encoding characteristics to measure WSM congestion responsiveness under various streaming configurations and network conditions. We find WSM has a prominent buffering phase in which it sends data at a bitrate significantly higher than the steady-state playout rate. Overall, WSM is responsive to available capacity, but is often unfair to TCP. The additional characteristics we measure can be combined to guide emulation or simulation configurations and network traffic generators for use in further research.


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